Sharing a wide range of experiences and perspectives relating to mineralogy as a hobby

Sunday, March 27, 2011

A Mineralogical Hike near Baltimore, Maryland

This is a pleasant safe hike of just over two miles through accessible public terrain, mostly in Robert E. Lee Park. It offers pegmatites, serpentine barrens, and chrome pits. The trail begins by following the former railroad bed of the long abandoned Greenspring Branch from the off-road parking area along the northbound stretch of Falls Road just past where it crosses Jones Falls.

Very recently, while I was busy writing two articles for The Vug * assigned to me by twelve year old Jessica Simonoff, her father Bob headed here on his own to check it out. He didn't get very far before making a find worthy of ---and soon to be---the subject of its own post here at Mineral Bliss. Stay tuned for that one.

The trail passes through woodlands for the better part of a mile. To the right is Jones Falls. On the left is hillside with occasional cuts from the former train tracks. Schist comprises most of the rock displayed by these cuts. At approximately a quarter mile, a thick vein of milky quartz runs through the schist. About hundred yards farther along, veins of exposed pegmatite(see picture at left) display plenty of pink orthoclase, quartz and mica. One wonders whether beryl or apatite might linger somewhere within. These small pegnatites, however, have greater value as scenery. Taking even take a curious whack with a hammer could result in a destruction of public property rap worthy of rigid enforcement.

The trail continues to a foot bridge crossing Jones Falls. Just beyond, the stunted evergreens of the Bare Hills serpentine barrens, once one of the world's leading sources of chromite, are visible atop the hillside at right through still bare deciduous tree branches. The barrens then drop out of sight as the trail bears straight ahead through an area where old railroad ties still linger across it. Thereafter, it partially fades and divides. A trail to the right leads up to the barrens.

Upon approach, the rocks change quickly from mostly schist, quartz and feldspar to dull green brown serpentinite often dotted with chromite. The long out of print 1940 Natural History Society of Maryland Publication Minerals of Maryland by Ostrander and Price lists the following minerals as present: Chromite, talc, chalcedony, opal, baltimorite, crysolite, sepiolite (meerschaum), magnesite, chlorite, rhodochrome (pink clinochlore), gymnite in chalcedony (deweylite), dendritic wad, marmolite, williamsite, porcellophite, pyroxene, hyalite, hydromagnesite, and moss agate. Most of these minerals are said to have been collected at the barrens on the opposite side of Falls Road. For the last 40 years, at least, all of that land has been privately owned, mostly built over, and otherwise posted. Although the same serpentine barrens grace either side of Falls Road, the rocks here on this side appear duller and with less definition. Perhaps the species noted in Minerals of Maryland could be present, but little that met my eye encouraged optimism about the likelihood of spotting very many.

The intersecting trail to the right proceeds through the barrens in a westerly direction. The rocks along it appear marginally more interesting, occasionally revealing readily identifiable chrysotile, talc, and magnesite. Another attraction is the pit pictured at right.

After about a quarter mile, it ends where a trail to the right heads out of the serpentine barrens, back into the woodlands and downhill to meet the railroad bed trail near the Jones Falls footbridge. About halfway from here to the parking lot and just above a swampy area between the trail and Jones Falls, I look away from the rocks and take in the green shoots of lillies and skunk cabbage below, incipient leaves sprouting from bushes, and the incessant chirping of a myriad frogs. However wonderful that spring is upon us, it will lead to briars and brambles making the barrens above less pleasurable to navigate.

* For the past several weeks, time I normally devote to Mineral Bliss was spent researching and writing two articles for The Vug , one on Maryland carrollite, another on Maryland wulfenite. It is expected that they will be on line and in print by April 16, in time for the Rochester Mineralogical Symposium.